If I was driving a race car, I'd worry about weight. It's my DD and I love to open the roof on a beautiful country road and cruise the back roads of GE, NL and BE. To each is own and respect your decision not matter what you choose.

That was actually the correct spelling, from the French word 'fibre" which in turn came from the Latin word "fibra", before some illiterate American hicks who like sleeping with their sister ruined the spelling

Performance difference will be minute. Carbon roof looks great on certain paints, especially Melbourne and alpine, but I love my moon roof. It's nice even in winter to crack it open to prevent the car from getting stuffy. While i still feel a twang of regret when I see cf, it's quickly overcome by the utility and luxury of the moon roof. I've chosen to shed weight in the exhaust and rims to even up the weight score with the cf guys.

I'm pretty sure all of us on here are Sebastian Vettels and can notice a couple of millimetres shift in the centre of gravity's location.

So what exactly is the performance delta between the two cars anyway? Because what theoretically works on paper doesn't always translate to the real world. So has there ever been any documented evidence of the carbon fibre roof actually leading to measurable performance gains? Or is this more like a ricer buying carbon fibre parts off eBay for his Civic and convincing himself that he has a racing car?

I hope everyone who is sooo performance oriented that they are making the argument that a CF roof makes a difference at the track also have DCT and the competition package. Because, the minor weight difference of the CF will not make as big a difference as these other options will. I'm just sayin...

There are what, maybe 3 people on this board who could throw down a faster lap in a CF vs. sunroof coupe - all other things being equal. You'd cut more time off a lap with a good set of R comp's than a roof ever could. It's an aesthetic choice much more than performance.

Before I bought mine, I did an epic 3 day drive through CA in a rented E92 with CF roof. Loved the car but several times every day, I wanted to pop open the roof to view the beautiful scenery. That was the deciding factor for me even though I love the look of the CF. Oh yeah, and I'm old

Kudos to bmw because a 15lb lighter roof makes the m3 an inherently better platform for club and pro racing. And 15lbs at roof height might not be anything for your avg joe hpde-er but it is in racing. The weight of a sunroof is pretty bad for performance on track and that difference I bet a fast hpde guy could feel.

Kudos to bmw because a 15lb lighter roof makes the m3 an inherently better platform for club and pro racing. And 15lbs at roof height might not be anything for your avg joe hpde-er but it is in racing. The weight of a sunroof is pretty bad for performance on track and that difference I bet a fast hpde guy could feel.

Perhaps, but if you really want a dedicated race car then an M3 is a subpar platform for that. It's quite expensive, and for all that cost it's still underpowered, overweight, and requires a long laundry list of mods before being ready for racing. It's not a particularly fast car for the money either. For such a price tag there are many platforms that are more suited for building a race car, for example a slightly used C6 Z06, Cayman R, GTR, or even a Boss 302.

Perhaps, but if you really want a dedicated race car then an M3 is a subpar platform for that. It's quite expensive, and for all that cost it's still underpowered, overweight, and requires a long laundry list of mods before being ready for racing. It's not a particularly fast car for the money either. For such a price tag there are many platforms that are more suited for building a race car, for example a slightly used C6 Z06, Cayman R, GTR, or even a Boss 302.

Perhaps, but if you really want a dedicated race car then an M3 is a subpar platform for that. It's quite expensive, and for all that cost it's still underpowered, overweight, and requires a long laundry list of mods before being ready for racing. It's not a particularly fast car for the money either. For such a price tag there are many platforms that are more suited for building a race car, for example a slightly used C6 Z06, Cayman R, GTR, or even a Boss 302.

I'd agree for a track day car but things are a lot more complex when it comes to club racing which my previous post was directed at. BMWCCA, SCCA, and NASA all have classes for M3s which don't allow some of the cars you mentioned. And GTRs are expensive to track (fuel, tires, brakes,..)